A286 Screws
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A286 / Alloy 660 for excellent high temperature oxidation resistance
Excellent high temperature oxidation resistance to 1300°F / 700°C
Maintains high strength at elevated temperatures
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RAYCHIN LIMITED
Specialist in A286 Screws · Hex Head · Socket Head · Torx Drive · Set Screws · CustomA286 Screws: High-Temperature Superalloy Screws for Critical Fastening Applications
RAYCHIN LIMITED is a recognized expert in A286 screws — from A286 hex head screws, A286 socket head cap screws, A286 Torx screws, A286 set screws to custom non-standard screw configurations. A286 (UNS S66286) is an iron-nickel-chromium superalloy strengthened by precipitation hardening. Also designated as Alloy 660, it maintains exceptional strength and oxidation resistance up to 700°C (1292°F), making it the preferred material for high-temperature screw applications in gas turbines, pressure vessels, heat exchangers, valve assemblies, power generation, aerospace, and oil & gas (sour service). A286 screws are specifically designed for applications requiring high strength-to-weight ratio, excellent creep resistance, and reliable fastening in high-temperature environments. The alloy's thermal expansion coefficient closely matches that of austenitic stainless steels, preventing loss of preload during thermal cycling in flange connections and pressure boundary applications. Our portfolio includes screws manufactured to NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN and KS standards. Engineered for extreme environments where high-temperature strength, creep resistance, and corrosion resistance are critical. A286 screws are supplied in solution annealed and precipitation hardened conditions with full traceability and third-party certifications.
Complete Range of A286 Screws – Head Styles & Configurations
A286 Hex Head Screws
A286 hex head screws manufactured to ASME B18.2.1, DIN 931, DIN 933, and ISO 4014/4017 standards. Available in hex cap screws, heavy hex screws, and hex bolts. Features a six-sided head for external wrenching, providing high torque capability and positive drive. Ideal for high-temperature applications up to 700°C in pressure vessels, flange connections, and structural assemblies. Available in sizes from #4 to 2" (M3 to M48) in various lengths. Supplied in Class A, B, or D conditions per ASTM A453. Precision rolled threads for superior strength and consistency. Available with UNC, UNF, and metric coarse/fine threads.
A286 Socket Head Cap Screws
A286 socket head cap screws manufactured to ASME B18.3, DIN 912, and ISO 4762 standards. Features a cylindrical head with a hexagonal socket drive, providing high clamping force and clean appearance. The controlled fillet under the head reduces stress concentration and improves fatigue life. Ideal for high-temperature applications up to 700°C in gas turbines, vacuum chambers, and semiconductor equipment. Available in sizes from #0 to 1" (M1.6 to M24). Low head and button head configurations also available. Precision rolled threads for superior fatigue resistance.
A286 Torx Drive Screws
A286 Torx screws feature a 6-point star-shaped drive pattern (hexalobular per ISO 10664) that provides superior torque transfer and resistance to cam-out. Available in button head (DIN 7380/ISO 7380), flat head (DIN 7991/ISO 10642), and pan head configurations. The Torx drive allows for higher clamping loads without damaging the recess, making these screws ideal for high-vibration and high-temperature environments. Ideal for exhaust systems, manifold assemblies, and aerospace applications. Available with tamper-resistant Torx drive for security applications.
A286 Set Screws
A286 set screws manufactured to ASME B18.3, DIN 913-916, and ISO 4026-4029 standards. Available with various point styles: cup point, cone point, flat point, and half-dog point. Designed for securing rotating parts such as gears, pulleys, and shafts operating at elevated temperatures. The cup point style provides maximum holding power by biting into the shaft surface. Ideal for gas turbine components, exhaust systems, and high-temperature shaft assemblies. Available with hex socket or slotted drive.
A286 Screws – API & NACE Compliant
A286 screws certified to NACE MR0175 / ISO 15156 for sour service applications in oil and gas industry. Class D condition with controlled hardness ≤ 35 HRC per API 20F BSL2 & BSL3 requirements. Suitable for wellhead equipment, valve assemblies, subsea connections, and refinery applications exposed to H₂S environments. Available in all head styles with 100% hardness testing and Charpy impact testing at -196°C per Class D requirements. 100% NDT available including PMI, UT, and MPI.
Custom & Specialty A286 Screws
Need a special head style, unusual drive configuration, or custom length for your high-temperature application? RAYCHIN engineers work with you to produce custom A286 screws to your drawing. Options include shoulder screws, captive screws, screws with drilled heads for safety wiring, and special thread forms. Expert heat treatment (solution annealed at 982°C followed by precipitation hardening at 718°C for 16 hours) precisely controlled for each batch. Manufactured to NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN, KS standards.
Key Benefits of A286 Screws
High-Temperature Strength Retention
Maintains high strength up to 700°C, with stress rupture testing at 650°C required per ASTM A453 (386 MPa min for 100 hours). Ideal for turbine and pressure vessel applications.
Multiple Head Styles Available
Hex head for external wrenching, socket head for high clamping force, Torx drive for superior torque transfer, set screws for shaft retention. Custom configurations available.
Sour Service Approved
NACE MR0175 / ISO 15156 qualified for H₂S environments; Class D with hardness ≤ 35 HRC meets API 20F and API 6A requirements for oil and gas applications.
Thermal Expansion Matched
Thermal expansion coefficient (16.0-16.5 x 10⁻⁶/°C) closely matches austenitic stainless steels, preventing loss of preload during thermal cycling.
Oxidation Resistance
Excellent oxidation resistance up to 815°C continuous service and 982°C intermittent. Forms protective Cr₂O₃ scale for long-term durability.
Cryogenic Toughness
Maintains ductility and impact strength down to -196°C, with Charpy testing available per Class D requirements (40 J min).
Manufacturing Standards for A286 Screws
RAYCHIN LIMITED manufactures A286 screws to the following national and international standards, ensuring full compliance for projects worldwide. Both standard and non-standard custom configurations are available.
Screw Dimensional Standards
All dimensional standards available in UNC, UNF, UNJF-3A per MIL-S-8879, and metric thread configurations. Standard sizes from #0 to 2" (M1.6 to M48).
International Standards & Global Designations for A286 Screws
To serve clients worldwide, RAYCHIN LIMITED manufactures A286 screws from material conforming to the following national and international specifications. This ensures full compliance for projects in the Americas, Europe, Asia, and the Middle East.
UNS S66286 Alloy 660 ASTM A453 AMS 5732 AMS 5737 NACE MR0175 1.4980 API 20F GH2132 SUH660 NAS1351
Chemical Composition (Weight %) – A286 Superalloy (UNS S66286 / 1.4980)
Our A286 screws are produced from melts that strictly conform to the limits below per ASTM A453 / AMS 5731. The high nickel and chromium content provide excellent oxidation resistance, while titanium and aluminum enable precipitation hardening through gamma-prime (γ') phase formation. Molybdenum and vanadium contribute to solid solution strengthening, and boron enhances creep resistance.
Expert note: The combination of titanium and aluminum promotes the formation of Ni₃(Al,Ti) gamma-prime precipitates during aging, which provide A286 with its exceptional high-temperature strength. Boron addition (0.001-0.010%) significantly improves creep resistance by strengthening grain boundaries. With nickel content of 24-27%, A286 offers excellent resistance to chloride stress corrosion cracking and maintains a stable austenitic structure from cryogenic temperatures up to 700°C.
Complete Mechanical Properties of A286 Screws (per ASTM A453)
A286 screws are supplied in the solution annealed and precipitation hardened condition (982°C solution treat + 718°C age for 16 hours). ASTM A453 defines multiple classes for different strength levels and size ranges. The data below represent minimum requirements per ASTM A453/A453M unless otherwise noted.
Tensile Requirements by Class – ASTM A453 Grade 660
Hardness Requirements for Screws
For NACE MR0175 / API 20F sour service applications, Class D with maximum hardness 35 HRC is required and 100% hardness testing is mandatory.
Impact Properties (Charpy V-Notch)
Class D screws used in sour service applications are Charpy impact tested at -196°C with 40 J as the minimum qualifying requirement.
Stress Rupture Properties (650°C / 1200°F)
A critical requirement for high-temperature screws is stress rupture resistance. Per ASTM A453, Class A, B, and C materials must meet the following:
Note: Class D does not have a stress rupture requirement (marked "NR" in the standard).
Temperature-Dependent Yield Strength
The following table shows typical yield strength (0.2% offset) at elevated temperatures for A286 in the fully heat-treated condition.
Elevated Temperature Oxidation Resistance
A286 maintains anti-tensile strength not less than 885 MPa at 500°C with stress retention greater than 88.35%, making it the optimal choice for high-temperature screw applications.
Physical Properties of A286
Thermal Expansion Properties of A286 Screws for Flange Connections
A286 screws are specifically designed for use with austenitic stainless steel components (A182 F304, F316, F321) operating at elevated temperatures. Their thermal expansion coefficient closely matches that of stainless steels, preventing loss of preload during thermal cycling – a critical feature for maintaining gasket stress and preventing leaks in high-temperature flange connections.
This expansion match is critical for maintaining seal integrity in high-temperature applications such as refinery piping systems, power generation HRSG connections, and chemical processing equipment. Using A286 screws with stainless steel components ensures uniform thermal expansion and sustained clamp load.
API 6A & NACE MR0175 Compliance for A286 Screws
A286 screws are widely used in oil and gas applications requiring sour service resistance. Per API 6A and API 20F, A286 Grade 660 Class D is approved for H₂S service with maximum hardness of 35 HRC.
Heat Treatment & Microstructural Stability of A286 Screws
Optimal mechanical properties in A286 screws are achieved through a two-step heat treatment:
- Solution Annealing: 982°C (1800°F) for 1 hour, oil quench or water quench. This dissolves carbides and prepares the matrix for precipitation hardening.
- Aging (Precipitation Hardening): 718°C (1325°F) for 16 hours, air cool. This forms coherent γ' (gamma-prime) precipitates [Ni₃(Al,Ti)] that provide high-temperature strength.
Metallurgical studies show that controlled aging at 718°C ensures optimal γ' formation while avoiding η phase precipitation, maximizing creep resistance and long-term stability up to 700°C.
Corrosion Resistance of A286 Screws
While A286 is primarily selected for high-temperature strength, it also offers good corrosion resistance in many environments due to its high chromium (14-16%) and nickel (24-27%) content. The alloy exhibits excellent oxidation resistance up to 700°C continuous service and 815°C intermittent service.
Oxidation and Scaling Resistance
The chromium content provides excellent resistance to oxidation and scaling. A286 screws form a protective Cr₂O₃ scale that prevents further oxidation at elevated temperatures. They provide excellent oxidation resistance up to 815°C in continuous service and up to 982°C for intermittent service.
Corrosion in Other Environments
Critical Corrosion Considerations for Screws
- Oxidation Resistance: Excellent oxidation resistance up to 815°C in gas turbine and exhaust environments. Suitable for continuous service up to 700°C.
- NACE MR0175 Compliance: A286 is qualified for sour service (sulfide stress cracking resistance) in oilfield equipment per NACE MR0175/ISO 15156. Class D with maximum hardness 35 HRC is preferred for sour applications.
- Temperature Limitations: Maximum service temperature for continuous service is 700°C (1300°F). For intermittent service, temperatures up to 815°C are acceptable.
- Galvanic Corrosion: When paired with lower-grade materials, galvanic corrosion should be considered. A286 is compatible with stainless steels and nickel-based alloys.
- Non-Magnetic Property: A286 is essentially non-magnetic (permeability ≤ 1.01), making it suitable for applications requiring non-magnetic components such as MRI equipment and sensitive instrumentation.
Special focus: A286 Screws for High-Temperature & Critical Applications
For critical applications requiring high-temperature strength, oxidation resistance, and corrosion resistance, RAYCHIN offers A286 screws manufactured to ASTM, ASME, NACE, and customer-specific specifications. Our capabilities include:
- Gas Turbines & Power Generation: Turbine casing screws, combustion chamber fasteners, exhaust manifold screws, HRSG connections, steam turbine components.
- Pressure Vessels & Heat Exchangers: Flange screws, tube sheet fasteners, reactor closures, autoclave bolting.
- Oil & Gas / Sour Service: Wellhead equipment screws, valve assembly fasteners, subsea connections, refinery piping, NACE MR0175 applications.
- Aerospace: Engine mount screws, thrust nozzle fasteners, transmission components, missile guidance systems, satellite components.
- Cryogenic Equipment: LNG facility screws, cryogenic storage tank fasteners, superconducting magnets, MRI systems.
- Chemical Processing: High-temperature reactor screws, reformer connections, heat exchanger fasteners, thermowell assemblies.
- Automotive & Motorsports: Turbocharger screws, exhaust manifold fasteners, high-performance engine components, heat shield attachment.
- Head Styles: Hex head screws (DIN 931/933, ASME B18.2.1), socket head cap screws (DIN 912, ASME B18.3), Torx screws (DIN 7380/7991), set screws (DIN 913-916).
- Thread Specifications: UNC/UNF, metric coarse/fine, UNJF-3A per MIL-S-8879 – all classes up to 3A/6g.
- Surface Treatments: Silver plating per AMS 2410 for anti-seize, passivation per ASTM A967, Xylan coatings, PTFE, vacuum-compatible lubricants.
- Class Selection: Class A (standard strength), Class B, Class D (higher yield strength, API sour service), Cold Worked (maximum strength).
- Certifications: EN 10204 3.1/3.2 material certifications, NACE MR0175, API 20F, PED 2014/68/EU, ASME compliance.
All A286 screws are supplied with full traceability and third-party NDT upon request. Sizes available from #0 to 2" (M1.6 to M48) in all standard head styles. Material certifications included.
Why RAYCHIN LIMITED – The A286 Screw Authority
Metallurgical competence
Engineers on staff with deep expertise in precipitation hardening superalloys. We ensure proper solution annealing (982°C minimum) and precipitation hardening (718°C for 16 hours) for optimal high-temperature strength and creep resistance across all A286 screws. Every heat is verified by in-house testing and PMI verification. With 24-27% nickel and titanium-aluminum precipitation hardening, our screws provide exceptional strength up to 700°C while maintaining excellent corrosion resistance.
Global approvals & traceability
Our quality system is ISO 9001:2015 and AS9100D certified; we also comply with NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN and KS. Full material traceability from melt to final packaging (EN 10204 3.1/3.2). Third-party inspections (ABS, DNV, Lloyds) available. All A286 screws meet applicable AMS, ASTM A453, and NACE MR0175 requirements. API 20F certification available for Class D screws.
Precision head forming & threading
In-house CNC cold heading and precision thread rolling capabilities ensure consistent head dimensions and thread geometry. Precision rolled threads provide superior fatigue life and dimensional accuracy. 100% thread inspection available. Ultrasonic cleaning and passivation available for critical applications. Capable of producing Class 3A threads per NAS/AN/MS standards.
Custom solutions
Need a special head style, unusual drive configuration, or custom material certification for your high-temperature application? Our CNC heading and threading departments handle short runs with agility. We also provide specialized coatings, cryogenic impact testing, and NACE MR0175 compliant processing per customer requirements. Available in Class A, Class B, Class D (API sour service), and cold worked conditions.
Contact the A286 screw experts today
Request a quote for A286 screws, hex head screws, socket head cap screws, Torx screws, set screws & custom configurations – any global standard (NAS, AN, MS, ANSI, ASTM, ASME, SAE, API, NACE, ISO, DIN, KS), any quantity. Inquire about high-temperature screws up to 700°C, pressure vessel screws, NACE MR0175 sour service requirements, or cryogenic applications.
sales@ray-chin.com | +86 534 2166 566Our team speaks English, German, Mandarin, and Japanese – ready for your global procurement.
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